These should help:
First link is a Solex manual covering the 34-3 carburetor.
Second is a companion video to the manual.
With them you will be able to verify whatever the float adjustment procedure is after checking the height.
Additionally, you may find a better suited float height for the application than what is specified in the manual. I don't know of any who have done any recalibration work to that particular combination to work out the consequential bugs of the large venturi choke.
A inconsistant idle and off-idle hesitation will be your clues to a too-large venturi choke not sized properly to the engine displacement per-cylinder with the 34-3 when used on a 4-cylinder 'Wing.
To compensate for the large 34-3 choke and tract diameter mismatch, a manifold with smaller diameter fuel tracts will help increase airspeed (velocity) through the venturi so that the carburetor sees a better signal for the circutry.
In short, there is no compensation for the larger cross-sectional area of the runners for the manifold in that conversion package. Recalibration may help though. Unfortunately it may also magnify some other problem as a result in its correction.
I would send it back.
I'd PM the current purveyor of PVC manifolds and talk with him about his results with a small diameter manifold and a Solex 34-3 variant.
A member here, "Sergei" over in Russia somewhere, has had some good reports of the conversion you purchased "out of the box" with just tuning, though I don't recall what his final thought of it was. I think it was not as glowing as when first spoke of.
Hit him up for a report before you reach your final thoughts of it.
I can't give glowing results of a 34-3 myself. The 34-3 is the only large base flange Solex.
Any small bas flange Solex will give better idle results than the 34-3. Top-end losses in using a smaller base flange carb are spoke of on forums as though they are relevant when, in fact, they are completely irrelevant.
There are other options as well once you dive a little deeper into becoming a Conversioneer. Big secondary 2-barrel Weber's and such...
The conversion you purchased emanates from direct competition with a better selling, better performing conversion using a small base flange 30-series Solex carburetor from a fella that is no longer with us.
Your current conversion has known problems inherent to its design.
If you keep it and tune it by your best ability, what you will find when done are the two idle problems I've mentioned above.
In any event let us know your next move on this conversion.
I started a thread looking for positive feedback on that conversion. No responses for a reason?
My final thought:
..keep the manifold, get a significant refund for the carburetor supplied based on basic engineering principles set by Solex for the Sellers improper selection and use of their carburetor as shown in both the linked manual and its companion video instruction of how to properly select and use a Solex carburetor for this, the intended Goldwing motorcycle application, buy a large-to-small base flange adapter and run 30/31 variant.